On Saturday 05 May 2007, Oliver Neukum wrote:
>Am Samstag, 5. Mai 2007 20:08 schrieb Antonino Ingargiola:
>> Now I don't want to abuse your kindness, but I (personally) would be
>> *really* interested in a similar fix for the FTDI usb-serial driver,
>> because many measurements I do use an FTDI device.
>
>Does this work?
>
>       Regards
>               Oliver
>----
>
>--- a/drivers/usb/serial/ftdi_sio.c    2007-05-05 20:21:41.000000000 +0200
>+++ b/drivers/usb/serial/ftdi_sio.c    2007-05-05 20:27:09.000000000 +0200
>@@ -1749,10 +1749,6 @@ static void ftdi_process_read (struct wo
>                       length = 0;
>               }
>
>-              if (priv->rx_flags & THROTTLED) {
>-                      dbg("%s - throttled", __FUNCTION__);
>-                      break;
>-              }
>               if (tty_buffer_request_room(tty, length) < length) {
>                       /* break out & wait for throttling/unthrottling to 
> happen */
>                       dbg("%s - receive room low", __FUNCTION__);
>@@ -1825,16 +1821,6 @@ static void ftdi_process_read (struct wo
>               dbg("%s - incomplete, %d bytes processed, %d remain",
>                               __FUNCTION__, packet_offset,
>                               urb->actual_length - packet_offset);
>-              /* check if we were throttled while processing */
>-              spin_lock_irqsave(&priv->rx_lock, flags);
>-              if (priv->rx_flags & THROTTLED) {
>-                      priv->rx_flags |= ACTUALLY_THROTTLED;
>-                      spin_unlock_irqrestore(&priv->rx_lock, flags);
>-                      dbg("%s - deferring remainder until unthrottled",
>-                                      __FUNCTION__);
>-                      return;
>-              }
>-              spin_unlock_irqrestore(&priv->rx_lock, flags);
>               /* if the port is closed stop trying to read */
>               if (port->open_count > 0){
>                       /* delay processing of remainder */
>@@ -1856,9 +1842,15 @@ static void ftdi_process_read (struct wo
>                             port->read_urb->transfer_buffer,
> port->read_urb->transfer_buffer_length, ftdi_read_bulk_callback, port);
>
>-              result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
>-              if (result)
>-                      err("%s - failed resubmitting read urb, error %d", 
>__FUNCTION__,
> result); +            spin_lock_irqsave(&priv->rx_lock, flags);
>+              if (priv->rx_flags & THROTTLED) {
>+                      priv->rx_flags |= ACTUALLY_THROTTLED;
>+              } else {
>+                      result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
>+                      if (result)
>+                              err("%s - failed resubmitting read urb, error 
>%d", __FUNCTION__,
> result); +            }
>+              spin_unlock_irqrestore(&priv->rx_lock, flags);
>       }
>
>       return;
>-
Oliver:

While running kernel-2.6.21.1-sd-0.48 + this and the other patch I mentioned,

Unforch, this patch doesn't seem to have effected my usb-serial problems, for 
upsd anyway, it's running at 47% of the cpu right now, while running sd-0.48.

Occasionally a stop and restart will fix it...  Nope.  On the restart, its 
about 3% _until_ something starts reading its output data file, which could 
be gkrellmBUPS, or its own gui, either one bounces it back up to 45+% of the 
cpu.  On a kernel where it works sorta right, as in a recent fedora kernel, 
its about 1.5%, and on even older 2.6.18ish stuff, this utility ran at .1% of 
the cpu regardless of who read its output data.  But that was with a pl2303 
adapter, which no longer works at all so I bought some ftdi based ones.

So the next boot will be to cfs-v10 + these.



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-- 
Cheers, Gene
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